Distribution Notes:

Biology:

This species occurs only in cloud forest habitats, where it nests in large epiphyte mats in the canopy, and occasionally in dead wood near ground level. Foundress queens occur under epiphyte mats, and in some cases pleometrosis occurs (a group of over five queens together with brood and small workers has been observed). Colonies are large, with many workers pouring forth when the nest is disturbed. Soldiers tend to stay deep within the colony. The feeding habits of this species are unknown. Foragers have never been observed outside of the nests. Observations have been almost entirely during the day, so they could forage nocturnally. Alternatively, they may have specialized and perhaps plant-derived food sources within the nests. Scattered mealybugs may be found on epiphyte roots in the nests (figure).

Notes:

Wilson (2003) considers this species to be a junior synonym of alfaroi. The two appear morphologically identical and differ only in color. However, P. innupta and P. alfaroi are sympatric in the Vara Blanca area of Braulio Carrillo National Park, and they seem to have different nesting habits. Pheidole innupta nests mainly under epiphyte clumps and is rarely obtained in Winkler samples. In contrast, P. alfaroi is known mainly from Winkler samples and presumably nests on the forest floor. We prefer to treat them as different species.

This species occurs only in cloud forest habitats, where it nests in large epiphyte mats in the canopy, and occasionally in dead wood near ground level. Foundress queens occur under epiphyte mats, and in some cases pleometrosis occurs (a group of over five queens together with brood and small workers has been observed). Colonies are large, with many workers pouring forth when the nest is disturbed. Soldiers tend to stay deep within the colony. The feeding habits of this species are unknown. Foragers have never been observed outside of the nests. Observations have been almost entirely during the day, so they could forage nocturnally. Alternatively, they may have specialized and perhaps plant-derived food sources within the nests. Scattered mealybugs may be found on epiphyte roots in the nests.

Comments

Pheidole innuptaHNS and Pheidole alfaroiHNS appear identical with respect to size, shape, surface sculpture, and pilosity. They differ in color, distribution, and nesting behavior. It is common in ant taxonomy to disregard color as a species specific trait because it often varies intraspecifically, especially in polytypic species with allopatric or parapatric color forms. But in this case the two species appear to remain distinct in sympatry, with very little evidence of intergradation.

Both species are so far only known from Costa Rica, although similar montane species occur in the mountains of Colombia. Pheidole innuptaHNS workers are dark brown to black; P. alfaroiHNS workers are light orange brown. Pheidole innuptaHNS occurs in cloud forest habitats in the northern cordilleras of Costa Rica, from the Cordillera Volcanica Central to the Cordillera de Guanacaste. Pheidole alfaroiHNS is only known from the Cordillera Volcanica Central. Pheidole innuptaHNS occurs in heavily forested areas, nesting under thick epiphyte mats either in the canopy or in gaps where epiphyte-laden branches have fallen. Pheidole alfaroiHNS occurs more on the ground, either under second growth forest or in cloud forest pastures, nesting under dead wood.

In the Project ALAS quantitative sampling along the Barva Transect in Costa Rica, intensive sampling was carried out at 1100m, 1500m, and 2000m elevation. The 1100m site was all dense primary forest. The 1500m site was an ecotone between primary forest and actively maintained cow pastures. The 2000m site was a mosaic of primary forest and regenerating second growth vegetation. Ants were collected using Winkler samples of sifted litter from the forest floor, flight intercept traps, and Malaise traps. At the 1100m site, P. alfaroiHNS was moderately abundant in all sample types, while P. innuptaHNS was rare, occurring in only one of 20 Malaise traps. At the 1500m site P alfaroiHNS was one of the most abundant ants, occurring in all sample types and in many hand collections of nests under dead wood, and P. innuptaHNS was absent. At the 2000m site, P. innuptaHNS workers were collected occasionally in Malaise traps and flight intercept traps, but never in Winkler samples from the forest floor litter. Pheidole alfaroiHNS was absent. These observations suggest that P. innuptaHNS and P. alfaroiHNS are ecological replacements, with P. innuptaHNS being arboreal and adapted to the coldest conditions and highest elevations, while P. alfaroiHNS is ground-nesting and adapted to slightly warmer, lower elevation, and/or more disturbed habitats. This is an interesting species pair to observe with respect to climate change.

Specimen Habitat Summary

Found most commonly in these habitats: 22 times found in cloud forest, 13 times found in montane wet forest, 15 times found in primary cloud forest, 7 times found in mature wet forest, 1 times found in elfin forest, 1 times found in mature cloud forest, 2 times found in montane pasture, 3 times found in cloud forest edge, 2 times found in secondary cloud forest, 2 times found in wet forest, ...

Found most commonly in these microhabitats: 17 times ex canopy tree, 8 times under epiphytes, 6 times ex sifted leaf litter from canopy, 2 times bajo de M/14, 4 times at bait, 1 times under stone, 1 times nest under epiphyte mat, 2 times nest under moss on dead wood, 1 times Cloud forest. Populous colony under thick epiphyte mat of large old treefall. R, 1 times cloud forest, road near reserve building and to ventana. pheidole colony in rot, 1 times under epiphytes in treefall, ...

Collected most commonly using these methods: 19 times search, 20 times fogging, 9 times Winkler, 4 times flight intercept trap, 5 times Malaise, 4 times bait, 2 times beating, 1 times sweep.

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